Image display

• US 7,088,058 B2
• Filed: 06/01/2004
• Issued: 08/08/2006
• Est. Priority Date: 07/18/2003
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Hamada, Satoshi, Noguchi, Toshiyuki, Shiota, Tetsuro
• Primary Examiner(s): Dinh, Trinh
• Assistant Examiner(s): LE, TUNG X
• Application Number:
  US10/520,334
• Publication Number:
  US 20050242741A1
• Time in Patent Office: 798 Days
• Field of Search: 315112-118, 315/169.4, 315/291, 315/224, 353/31, 353/69, 353/101, 353/94
• US Class Current: 315/291
• CPC Class Codes: G03B 21/16 Cooling; Preventing overheating
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: H04N 5/7416 involving the use of a spatial light modulator, e.g. a light valve, controlled by a video signal
• CPC Class Codes: H04N 9/31 Projection devices for colour picture display , e.g. using electronic spatial light modulators [ESLM]
• CPC Class Codes: H04N 9/3144 Cooling systems cooling of liquid crystal cells in general G02F1/133382; cooling of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/16
• CPC Class Codes: H04N 9/3155 for controlling the light source light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406
• CPC Class Codes: H05B 41/2928 for protecting the lamp against abnormal operating conditions
• CPC Class Codes: H05B 41/36 Controlling
• CPC Class Codes: H05B 41/39 continuously
• CPC Class Codes: H05B 47/18 via data-bus transmission

Abstract

An image display device which has a display element that optically modulates an incident light for displaying an image. A lamp is a light source of the incident light to the display element. A lamp driver drives the lamp. A lamp power level calculator calculates a driving power level of the lamp corresponding to a level of an input video signal. A lamp temperature controller controls a lamp temperature depending on changes in the input signal from the lamp power level calculator so as to change the lamp temperature within a predetermined range in response to fluctuations of the input video signal. This image display device can further include a projection lens for projecting and displaying images formed in the display element on a screen.

Claims

1. An image display device comprising:

a display element which optically modulates an incident light for displaying a video image;

a lamp which is a light source of the incident light to the display element;

a lamp driver for driving the lamp;

a lamp power level calculator for calculating and outputting a driving power level of the lamp in accordance with a level of an input video signal; and

a lamp temperature controller for controlling a temperature of the lamp depending on a change in an input signal from the lamp power level calculator so as to change a temperature of the lamp within a predetermined range in response to fluctuation of the input video signal,

wherein the output driving power level of the lamp varies as a monotonically increasing function of a dynamic range of the input video signal.

2. The image display device as defined in claim 1, wherein the lamp temperature controller is a lamp driving level correcting unit for correcting a lamp driving level in response to fluctuation of the input video signal;

and the lamp driving level correcting unit comprises;

a lamp driving level signal integrator for applying time integration to an input from the lamp power level calculator; and

a lamp driving level corrector for correcting an input signal from the lamp power level calculator using an input signal from the driving level signal integrator.

3. The image display device as defined in claim 1, wherein the lamp temperature controller comprises:

a fan control signal generating unit for controlling a number of revolutions of a fan for temperature control in accordance with an input from the lamp power level calculator,

a lamp temperature control fan controlled by an input signal from the fan control signal generating unit; and

the temperature of the lamp is changed within a predetermined range by controlling the number of revolutions of the fan in response to fluctuation of the input video signal.

4. The image display device as defined in claim 3, wherein the fan control signal generating unit comprises:

a lamp driving level signal integrator for applying time integration to an input signal from the lamp power level calculator; and

a fan control signal generator for controlling the number of revolutions of the fan in accordance with an input signal from the lamp power level calculator and an input signal from the lamp driving level signal integrator.

5. The image display device as defined in claim 1, wherein the lamp temperature controller comprises:

a lamp driving level correcting unit for correcting a lamp driving level in response to fluctuation of the input video signal;

a fan control signal generating unit for controlling a number of revolutions of a fan for temperature control in accordance with an input signal from the lamp power level calculator;

a lamp temperature control fan controlled by an input from the fan control signal generating unit; and

the lamp driving level is corrected in response to fluctuation of the input video signal, and the number of revolutions of the fan is controlled in response to fluctuation of the input video signal so as to change a temperature of the lamp within a predetermined range.

6. The image display device as defined in claim 5, wherein the lamp driving level correcting unit comprises:

a lamp driving level signal integrator for applying time integration to an input signal from the lamp power level calculator; and

a lamp driving level corrector for correcting an input signal from the lamp power level calculator using an input signal from the driving level signal integrator.

7. The image display device as defined in claim 5, wherein the fan control signal generating unit comprises:

a lamp driving level signal integrator for applying time integration to an input from the lamp power level calculator; and

a fan control signal generator for controlling the number of revolutions of the fan in accordance with an input signal from the lamp power level calculator and an input signal from the driving level signal integrator.

8. The image display device as defined in claim 1 further comprising a projection lens for projecting and displaying an image formed in the display element on a screen.

9. The image display device as defined in claim 2 further comprising a projection lens for projecting and displaying an image formed in the display element on a screen.

10. The image display device as defined in claim 3 further comprising a projection lens for projecting and displaying an image formed in the display element on a screen.

11. The image display device as defined in claim 4 further comprising a projection lens for projecting and displaying an image formed in the display element on a screen.

12. The image display device as defined in claim 5 further comprising a projection lens for projecting and displaying an image formed in the display element on a screen.

13. The image display device as defined in claim 6 further comprising a projection lens for projecting and displaying an image formed in the display element on a screen.

14. The image display device as defined in claim 7 further comprising a projection lens for projecting and displaying an image formed in the display element on a screen.